linux-kernel - Re: [PATCH net-next V3] tun: add eBPF based queue selection method

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1512684709.25033.18.camel@gmail.com>
Date:   Thu, 07 Dec 2017 14:11:49 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Jason Wang <jasowang@...hat.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     mst@...hat.com, willemdebruijn.kernel@...il.com,
        tom@...bertland.com, aconole@...hat.com, wexu@...hat.com
Subject: Re: [PATCH net-next V3] tun: add eBPF based queue selection method

On Mon, 2017-12-04 at 17:31 +0800, Jason Wang wrote:
> This patch introduces an eBPF based queue selection method. With
> this,
> the policy could be offloaded to userspace completely through a new
> ioctl TUNSETSTEERINGEBPF.

Sorry for the delay, I see this patch was merged already.

...

>  static void tun_free_netdev(struct net_device *dev)
>  {
>  	struct tun_struct *tun = netdev_priv(dev);
> @@ -1996,6 +2068,9 @@ static void tun_free_netdev(struct net_device
> *dev)
>  	free_percpu(tun->pcpu_stats);
>  	tun_flow_uninit(tun);
>  	security_tun_dev_free_security(tun->security);
> +	rtnl_lock();
> +	__tun_set_steering_ebpf(tun, NULL);
> +	rtnl_unlock();
>  }

I am pretty sure tun_free_netdev() (aka ->priv_destructor()) can be
called under RTNL (say from register_netdevice())

So this will dead lock badly ?